Auger rock drill bit



June 26, 1951 F. L. coRY El AL 2,558,341

AUGER ROCK DRILL BIT Filed March 11, 1949 1 7.11. Hayden INVENTOHSATTORNEYS Patented June 26, 1951 UNITED STATES PAT ENT OFFICE AUGER ROCKDRILL err Frank Lawrence Cory, Central Valley, and Ernest Albert Hayden,Callahan, Calif.

Application March 11, 1949, Serial No. 80,952

5 Claims.

This invention relates to rock drill bit construction. Moreparticularly, the invention has reference to an improved bit, novellydesigned to per- One or a combination of these conditions may complicateand make difficult the drilling operations. For example, in damp clayground, the drilling dust tends to form around the drill stem, making acollar. Or, in caving ground small rocks will fall behind the drill bitforming an obstruction when an attempt is made to withdraw the drillingsteel. time may be lost in drilling a single hole, and

very often long lengths of drill steel cannot be,

removed. In such cases, it may be necessary to drill another hole nearbyin order to achieve the results desired, and subsequent blastingoperations in most cases will damage the unremoved drill still beyondpossible reuse.

The purpose of the present invention, accord ingly, is to save valuabletime andmaterial, and to permit drilling in types of earth and rockheretofore avoided, thus to make earth excavation cheaper and manyprojects possible that have heretofore not been feasible, using theusual drilling methods.

To this end, we provide a rock drill bit which in basic essentials isconventionally formed, so

far as actual drilling of the hole is concerned;

and special cutters or augers formed on the drill shank or side surfacesof the drill bit, or at any other point back, of the cutting. face ofthe bit, said augers being specially designed so as, in effect, to causethe rock drill to auger its way back out of the drill hole, where-it isdesired to remove the drill.

With the foregoing and other objects in view which will appear as thedescription proceeds, the invention consists of certain novel details ofconstruction and combinations of parts, hereinafter more fully describedandpointed out inthe claims, it being understood that changesmay be madein theconstruction andaarrangement of parts without departing from, thespirit of the invention as claimed.

Referring to the drawings Fig. l is a side elevatio'nalview of a rockdrill bit and adjacent portion of a drill shank, showing one form of theinvention applied thereto.

Fig. 2 is a section on line 2-2 of Fig. 1. Referring to the drawings indetail, 5 designates generally a drill shank to which is attached Thus,many hours of ,1 of the drill hole. 40

a drill bit 6 having a portion of the shank 5 constitute the headportion of a rock drill.

opening at ill on the cutting face of the bit.

The bitin the present instance is formed with,

radial cutters H defining between them depressions I2. back of therespective cutters H, said shoulders alternating with thedepressions l2,as readily seen from Fig. 2.

All. the above is conventional rock. drill bit construction and does notper se constitute the present invention.

At this point, and for aibetter understanding hr the invention, it isappropriate to discuss the manner of use and operating characteristicsof,

a conventional rock drill bit as described above.

As the drilling proceeds, a blast of air. or air and water is sentthrough the bores 8, 9 and is blown, This is for. the purpose ofcarrying the drillings and small stones out of,

outthe opening II].

the drill hole.

It will be readily seen by reference to Fig. 2. that when this blastmoves backwardly around, the drill bit for the purpose stated above, itwill ;pass.through the spaced apart grooved or depressed portions 12 ofthebit- This, of course, is because the outer side walls of the cuttersll will be in. engagement with the side wall of the drill hole so thatthe air blast is forced. rearward-. ;ly through the clearance spaces ordepressions l2 1 between the respective cutters.

The result is that there is what amounts tea dead air space immediatelybehind each cutter.

II between each shoulder,l3 and the sidewall mud, andYother materialtends to lodge in this dead, air space- Accordingly, when an attempt. ismade to remove the drill, the drill sticks in the drill hole.

In accordance with the drill bit, said cutter members on the drillbitbeing best termed cutting augers and being generally designated bythe reference numeral I4.

are applied, or on other factors. tration of the invention, four augersI4 are il-, lustrated purely forthe sake of example in ShOW-r We believethe number of these augers II can vary depending on the characteristicsof the earth or rock being drilled, the particular formation of the rockdrill bit to which the augers threaded socket receiving. threaded stud iformed on the shank 5. When considered together, the bit 6 and theillustrated,

Shank 5 has an axial bore 8 communicating with bore 9 of the bit, bore 9Additionally, shoulders I3 are defined- Small hard stones, drillings,

invention, a plurality of spaced cutter members are provided asprojections from the side walls of the drill shankand In the illus- Eachauger [4 in its preferred form is pitched away from the cutting face ofthe bit, this being for the purpose of causing the drill to auger itsway backwardly out of the drill. hole while still rotating in the samedirection as it was rotating while moving forwardly and drilling thehole. Each auger, in this connect-ion, is pro vided with a top face I5disposed in a plane that is at a slight angle from a plane perpendicularto the axis. of the drill. Each auger, additionall'y, has a-bottom faceI6 which is at a greater angle to said perpendicular plane, said top andbottom faces converging to meet at the front cutting edge I I of theauger. Thus, each cutting auger I4 is of approximately triangularshape-,having a rear. face 18. It has been found that, in. averagedrilling conditions, the pitch of the bottom of the auger should beabout 35 degrees, and the" top pitch about 8 degrees, to the horizontal.

We also provide another annular row of spaced augers, or more than oneother row. These are disposedv more remote from the cutting face of thedrill bit,. and for example they can comprise a row of cutting augers l9locatedon the drill shank 5. Or, an annular row of cutting augers couldbe provided on a Washer which can be interposed between the drill shankand.

drillbit in some bit constructions.

In any event, if one or more rows of augers l9v are provided, they areof roughly thesame formation and characteristics as the augers Id. Inthe present instance, the augers l9 have top faces pitched like the topfaces [5, and bottom faces 2|, rear faces 22., and cutting edges 23.These in the present instance do not extend laterally as far as thecutting augers M, as readily seen from Fig. 1 and Fig. 2. Rather, thefirst row of augers 19 can operate to chew into those cuttingswhichmight otherwise bind against the enlarged lower end of the drillshank, where.- upon as the drill augers its way back out of the drillhole, the larger augers 14 can act upon those cuttings which havealready been chewed up by the augers l9, and can also act upon otherctittings which are outside the reach of the augers In any event, whenthe drill .is to. be withdrawn, the operator continues rotating. thedrill in its original direction, shown by the arrow in Fig. 2. As. thedrill is withdrawn, it will drill. its way back through the cuttings, inthe manner described above, causing easy and speedy withdrawaljof. the,drill. In tests continuing over a long period of time, the augers havebeen found to act exactly as stated above.

What is claimed is:

1,. A rock drill bit comprising radial wings,

V radial". cutting edges on the lower end of said wingsa plurality ofradially extending ledge members. integral with the upper portion of thebit, the outermost surfaces of the ledge members extending outwardlyfrom the bit axis a distance no greater than the cutting edges of thebit, said ledge members being inclined upwards and having relativelysharp leading edges, the leading 4 edges of said ledge membersprojecting further outward from said upper portion than the trailingedges thereof.

2. A rock drill bit as in claim 1 having in combination therewith ashank, said bit being mounted at the lower end of said shank, anenlarged bell-shaped bit receiving portion on the lower extremity ofsaid shank, a plurality of radially extending secondary ledge membersintegral with i said shank and positioned on said bell-shaped portion,the outermost surfaces of said secondary ledges extending outwardly fromthe bit axis a distance no greater than the greatest diameter of theshank, said secondary ledge members being inclined upwards and havingrelatively sharp leading edges, theleading edges of saidsecondary ledgemembers projecting further outward from saidshank than the trailingedges thereof, said. first named ledge members extending further outward from the longitudinal axis of the bit than said secondary ledgemembers.

3. In a drill a head portion including means. at one end for drilling ahole, and a plurality of radially extending: ledge members rigid withthe side surface of said head portion, said ledge members having sharpleading edges and being inclined out of perpendicularity to the bitaxis, the outermost surfaces of the ledge members extending outwardlyfrom the bit axis a distance no greater than said hole drilling means.

4. In a drill ahead portion, means at one end thereof adapted fordrilling a hole, and a plurality of radially extending ledge members.rigid with the side surface of. the head portion, the. outermostsurfaces of the ledge members ex.- tending outwardly from the bit axis adistance :no

greater than the cutting edges of the bit, said ledge members beinginclined out of the perpendicularity to the bit axis. and havingrelatively sharp leading edges, the leading edges of. said ledge membersprojecting further. outward from said side surface than the trailingedges thereof.

5. In. a drill a head portion, means. at one end thereof. adapted fordrilling a hole, and a plurality of radially extending ledge membersvintegral with the side surface of said head portion, the outermostsurfaces of the ledge members extending outwardly from the bit axis adistance no greater than said hole drilling means; said ledge membersbeing disposed transversely of said head portion and. being inclinedslightly and having relatively sharp leading edges, the leading edges ofsaid ledge members extending transversely of the path of rotation ofsaid ledge members.

FRANK LAWRENCE CORY. ERNEST ALBERT HAYDEN.

REFERENCES CITED 7

